How to tell McIntosh MC452 and MC462 difference

Front panel and top is labeled. 

The changes besides the heat sinks and the model number are inside - my question is what are you looking to improve by moving from the 452 to the 462?  The improvements are headroom and distortion - I could see if you were looking for more power looking at the 611s or considering the new tube amps but if I were you shoes my 452 would have to be broken to buy the upgraded model.

Whoever said that there are no stupid questions needs to see this!

The newer model has different transformer covers.

Thanks Russ!

The reason I asked was not for sound quality. I asked because I heard that some unscrupulous people are selling 452s with 462 badging.

Well, the unscrupulous people would have to go to the trouble to replace the glass on the front, since the model number is right on the front below McIntosh.  

Not exactly what you were asking for but If cost (savings) is a factor, you might find a demo 452 still for a lot cheaper than a new 462. The audible difference between the 2 is negligible from all I researched. I was able to score one for a lot lesser than a new 462. 
 

Just received my 462 yesterday. Time to do some experimentation with differenc components.